The object of the present invention is a manual trigger dispenser device, primarily for liquids, for example for the hygiene of the house, the deodorization of environments, the treatment of fabrics before ironing, and the like.
Such devices have experienced a huge spreading, as is evident by looking at the shelves of supermarkets, especially for their ease of use and functionality. Many hundreds of millions of pieces are produced every year.
One of the reasons of the great circulation of such devices is the ability to spread a small amount of liquid in a large volume of space or on a wide surface.
This ability is due to the fact that, before being dispensed, the liquid is put under pressure in a pressure chamber in which a piston actuated by the trigger slides; the connection of the pressure chamber towards the outlet is closed by a pre-compression valve. Once a pressure value that makes the pre-compression valve open has been exceeded, the liquid proceeds at high speed towards a nozzle, formed so as to produce a more or less dense cloud of droplets, according to the needs.
The pre-compression valve therefore has an essential role for the proper functioning of the device. It must be such as to enable the dispensing of the liquid only upon exceeding a minimum pressure for smooth operation, but also so as not to require an excessive effort for operating the trigger for the user.
One of the most significant problems related to the pre-compression valve is the assembly of the same to the other components of the dispenser head, in general to the frame. A moment before dispensing, a pressure of 10 bar can be reached in the pressure chamber, which is equivalent, for the usual dimensions of such devices, to an action of about 12 Kilograms on the valve. Retaining it to the frame must therefore be extremely effective, as a failure of the coupling would make the valve labile and therefore it would be impossible to achieve the desired pressure in the pressure chamber.
There are several solutions for the assembly of the pre-compression valve to the frame of the dispenser head.
For example, some solutions are described in US2012/261438A1, WO2013/079418A1, EP1500436A1, U.S. Pat. No. 5,114,052A, WO2012/172276A1, U.S. Pat. No. 4,225,061A, WO99/53388A1 and International Applications WO2012/069939, WO 2012/156830, WO 2012/110861, WO 2011/128787 and WO 2011/128786 by the Applicant. In these solutions, the pre-compression valve is kept in position by a locking element that engages the frame. These systems have proved effective but require an additional component for implementation.
Another known solution is described in International Application WO 2008/116656. In this solution, the pre-compression valve is held to the frame by a wall of the cover of the dispenser head, which compresses the valve sleeve inside the seat of the valve itself. While this solution is effective, it requires a careful implementation of the head cover and particular caution and care in the assembly of the cover to the frame.